In modern communications technology, the various possibilities for communication involve not only voice and data transmission, but also images and video. This has increased the demands on all communication devices, in particular the demands on terminals.
A user of modern communication devices normally changes from one specific device, specialised in a certain type of communication technology, to another for a different type of communication. An example of the above is that a mobile communication terminal is used when there is no fixed terminal is available and a video conference call requires another terminal. However, in a near future, it is expected that one single terminal will be able to handle most of the different kinds of technology for communication, including voice, data, images and video communication. In addition to that, there is a conception of converging technologies in the field of mobile communication between the interrelated fields of telecommunication and data communication.
If an established communication session in a certain technology can no longer be upheld, if for example the network does not support the technology when a user leaves an area of coverage, there is a still need for continuing communication, for example by means of a parallel communication technology. However, ever since the introduction and initial definition of intelligent end devices, the device was seen as a non-replaceable node in the communication chain, as important session data was stored in the end device. Also within the specific technical field of IMS, this approach is continuing.
The published US patent application US 2005/0238002 discloses an IP Multimedia Subsystem architecture for multimedia services for handling of various procedures relating to IMS sessions. With respect to the present invention, the disclosure is directed towards an ability handling different generations of communication terminals resulting in enhanced compatibility. However, the compatibility disclosed is merely intended to handle a variety of communication terminals of the same kind, possibly of generations with different versions of for instance software packets installed.
Hence, it can be concluded that presently known technologies relating to IMS do not support session data being stored in a way that the terminal. A solution to the technological problem of allowing for a replaceable terminal, possibly of another kind and in particular an IMS client, is sought.